Generally, installation panels attached to the floors, walls and ceilings of gymnasiums or houses are made of long, flat cut wood with a certain length, width and depth, and they are attached by inserting, fitting and assembling several panels sequentially.
FIG. 1 is a perspective view showing a general method in which the installation panels are assembled and attached to an attachment surface A. According to the FIG. 1, long wooden supports 100 are arranged at fixed intervals sequentially, and the panels 101 are assembled on the supports 100. At this time, the panels 101 have projections 104, 105 and insertion grooves 102, 103 formed on the long edge and the short edge, are assembled and attached sequentially in an insertion and fitting method using the projections 104, 105 and insertion grooves 102, 103 and are fixed firmly by adhering the panels 101 to the supports 100 using fixing means such as nails or adhesives.
Since the panels 101 are made of wood, they are expanded and shrunk in accordance with the environment of depository or installation, that is, the variations of temperature and humidity. Generally, the total amount of expansion or shrinkage of the panels in the length is not severe, so that there is no defect in that direction. However, the amount of expansion or shrinkage of the panels in the width is severe.
Accordingly, when the panels 101 are shrunk, a gap between the panels widens and a space is formed so that alien substances can be put into the space. Also, it can spoil the beauty of the floor surface. In the case where the panels are expanded, their width widen, so that the panels 101 are stuck fast in the direction of width and accordingly there occurs a projection problem in which any assembled portion of the panels 101 cannot resist the expansion force and the portion rises as shown in FIG. 3(A).
Due to this problem, when making a installation of the inserting and fitting type panels, an extra gap x between panels 101 should be placed assuming that a displacement length caused by expansion of one panel is x. FIG. 2 shows an example of conventional panel attachment method, wherein the case that the extra gap 5x is placed every 5 panels 101, spacers 106 of 5x size should be inserted into every 5 panels and should be removed after finishing the installation.
However, since this conventional method is to make an extra gap in every determined panels 101 and insert the spacers 106 in consideration of the shrinkage and expansion rate of the panels 101, and remove the spacers 106 again after finishing the installation, the assembling work can't be carried out quickly due to the cumbersome work involved and needs an expert with much experience.
In addition, since the expansion or shrinkage rate of the panels 101 just before installation varies in transport procedure and keeping state and temperature/humidity of the place where the panels are installed, it is very difficult for an amateur to determine the extra gap and even the expert often fails to determine the extra gap precisely, and causes defects due to the shrinkage or expansion after installation.
And if many extra gaps are placed when constructing the panels, in case that the line L is drawn on the panels in the gymnasium or other similar place, the line L won't be drawn smoothly due to the extra gaps as shown in FIG. 3(B). So the appearance will not be good.
Also, when we have to remove the attached panels for repair and demolishment, it is difficult to separate the support or panels fixed with nails or strong adhesives, and it even causes a waste of resource and pollution, since the panels are broken and scrapped in the process of removal.